1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method and an apparatus for performing a hybrid automatic repeat request (HARQ) process in a wireless communication system for supporting inter-terminal communications.
2. Related Art
Recently, commercialization of a long term evolution (LTE) system as a next generation wireless communication system is supported in earnest. The LTE system is more rapidly spreading after necessity for supporting a large capacity service for demands of users as well as a voice service with high quality while guaranteeing activity of terminal users is recognized. The LTE system provides low transmission delay, a high transfer rate, high system capacity, and high coverage improvement.
On the other hand, the LTE system is developed to maintain compatibility with or coexist with a 2G communication system that is a global system for mobile communications (GSM) as a time division multiple access (TDMA) based communication technology and a 3G communication system that is a wideband code division multiple access (W-CDMA) based universal mobile telecommunication system (UMTS) in consideration of demands of a service provider that provides services to users and improvement of performance through improvement of a previously installed radio access network and an investment cost collection method for a previously invested wireless communication system.
In particular, recently, due to appearance of smart phones and tablet personal computers (PC), users of actual communication devices require services for easily obtaining or sharing desired information in desired places and at desired times. However, due to complexity or temporal delay of a wireless communication system, it is not easy for the wireless communication system to efficiently provide small but useful real time information for users in real life spaces.
On the other hand, a device to device (D2D) service is performed through D2D link among communication devices without a network such as a base station involved, which may be considered that the wireless communication system is desperately required to be developed and improved into a communication system for supporting an environment in which users may share and obtain various information items. Therefore, efficient data transmitting and receiving method and technology in the wireless communication system for supporting the D2D service are required.